This invention relates to surgical training and more particularly to device to be used as training subjects for heart surgery.
The known morbidity associated with cardiopulmonary bypass and the concept that trauma of access is often worse than the surgical procedure itself have resulted in the recent surge of interest in "off-pump" coronary surgery and minimally invasive direct coronary artery bypass (MIDCAB). These keyhole or port-access procedures are undergoing extensive development by companies such as Heartport of Redwood City, Calif., and Cardiothoracic Systems of Portola Valley, Calif. Indeed, there is already substantial experience with coronary artery grafting without cardiopulmonary bypass to indicate that this approach will become a permanent part of a cardiac surgeon's armamentarium.
The principal technical challenge for the interventional cardiothoracic surgeon in these "off-pump" and minimally invasive techniques is the performance of accurate coronary anastomoses on constantly moving target vessels of a beating heart. The targeted blood vessels are small (typically 2 mm in diameter) and constantly moving with each heartbeat. The significance of this endeavor is clearly reflected by the range of instruments and techniques which have been developed to reduce the motion of the segment of the coronary vessel to be grafted. Still, there is no alternative to the skill of the surgeon in determining the outcome of this surgical procedure.
Currently, no cost-effective training method is available to achieve this skill before attempting the technique on patients. Surgeons must now practice on patients, with the resultant occasional blocked anastomoses, occluded grafts, and myocardial infarctions. Although animal laboratories may be used to practice other surgical procedures, such as video-assisted left internal mammary artery (LIMA) harvest to gain experience and confidence before operating on patients, animal laboratories are not well suited for practicing "beating-heart" anastomoses. Unlike LIMA harvest, the animal model develops ventricular fibrillation very easily during beating heart procedures, usually within minutes of snaring the left anterior descending coronary artery for the procedure. Furthermore, animal laboratory facilities remain expensive and not widely available.
For these reasons, it would be desirable to provide improved devices and methods for practicing body lumen anastomoses on a beating or reciprocally moving object. It would be particularly desirable if such devices and methods overcame at least some of the problems noted above. For example, it would be desirable to provide a realistic, inexpensive, re-usable, and portable device on which a trainee can practice during his own time instead of being limited by the availability of animal laboratory facilities. Preferably the device should simulate a variety of different heart beat rates and beat displacements. As "beating-heart" surgery and other new approaches evolve and become established as standard practice, parallel training methods must be developed to prepare trained surgeons. The skill to perform a new surgical procedure can be developed through practices on inanimate simulators and, later, through preceptorship programs. At least some of the objectives should be met by each of the aspects of the present invention described hereinafter.